The invention relates generally to a new process for the purification of a stock solution of Strontium-90 and the subsequent separation of ingrowth Yttrium-90 from the purified Strontium-90 solution. Multi-Ci quantities of Yttrium-90 can be generated of sufficient quality for medical applications while minimizing the amount of waste generated.
Yttrium-90 (Y-90 ) is a radioactive nuclide used in medicine as a biological tracer and for treating cancer, arthritis, and arterial restenosis. Y-90 is a short-lived daughter product of the radioactive isotope strontium-90 (Sr-90). It decays with a relatively short half-life of 64.2 hours to stable zirconium-90 via high-energy β-decay. The Sr-90 isotope itself is one of the many byproducts of the decay of uranium fission reactors. It has a half-life of 29.1 years. The decay of Sr-90 proceeds according to the following scheme:

It is desirable to produce Y-90 with minimal contamination with the parent radioisotope, Sr-90 . This is particularly important for medical applications since Sr-90 is extremely toxic. The Y-90 produced should also be free of toxic metal ions and other radioactive isotopes commonly found in stock solutions of Sr-90 coming from nuclear reactors since these impurities would interfere with radiolabeling applications. For commercial purposes, the Y-90 extraction process should be uncomplicated, be relatively quick due to the short half-life of Y-90, produce multi-Ci quantities of Y-90, , and minimize the radioactive waste generated.
The most common process currently in use for extracting Y-90 from Sr-90 employs ion-exchange methods. However, ion-exchange resins are subject to radiation damage and are generally only suitable for sub-Ci quantities of Y-90 . Furthermore, to achieve acceptable Y-90 yields often requires long ion-exchange columns and large volumes of eluent. Other methods of extracting Y-90 from Sr-90 include solvent extraction, precipitation, and various forms of chromatography. Solvent extraction methods are complicated and typically produce volumes of liquid organic waste contaminated with Sr-90. None of these methods meet all of the desirable characteristics enumerated above.
Accordingly, a need exists for an uncomplicated method of generating Y-90 that produces a pure, high yield product suitable for medical applications, while at the same time minimizing waste products.